In recent years, among transportation systems in which a vehicle runs on a set track, a transportation system configured such that a vehicle runs without receiving power supply through contact wires has been put in practical use. Generally, a vehicle for such a transportation system without a contact wire is equipped with an electrical storage device (for example, a battery) for accumulating power, and the vehicle is configured to accumulate power in the electric storage device when the vehicle stops at a station and thereby to run on a set track.
As described above, operations of the vehicle are performed by using power supplied from the electric storage device in the transportation system without the contact wire. Accordingly, in order to perform the operations of the vehicle without trouble, it is necessary to calculate and manage the remaining capacity of the electric storage device.
Thus, there has heretofore been proposed a controller for an electric storage device (for example, Patent Document 1). The controller is configured to calculate the currently remaining capacity of the electric storage device on the basis of current data, voltage data, an amount of self discharge, and the like of the electric storage device.